To allow a fuel cell operating at low temperature to produce an adequate amount of current at acceptable potentials it is necessary to achieve a quick and efficient catalytic conversion of the reagents into products. At the anode, the fuel (hydrogen, methanol, ethanol, etc. . . . ) is oxidised producing H+ ions and other products; at the cathode, the oxidant (air or oxygen) is reduced developing O2− ions. Nowadays, all the electrocatalysts used in fuel cells operating at low temperatures are based upon platinum, either pure or supported on graphite. Electrodic materials are generally produced through an electrochemical reduction of precursors containing platinum and ruthenium on graphite nanopowders (carbon black). The result is an extremely thin black powder characterized by a large surface area and featuring graphite grains covered by metallic platinum. Cathodic electrocatalysts show platinum concentrations equal to 10-20 weight %, while anodic electrocatalysts may also have ruthenium, needed to limit the poisoning effects on the active sites caused by carbon monoxide and other poisoning agents such as halides, ammines, amides produced either by parasitic reactions such as fuel oxidation or present in the reagents in trace amounts. One of the main limits towards the large-scale use of this type of materials is their high cost; besides, it should be pointed out that not every metal may be deposited on graphite-based supports by electrochemical means.
It is reported in the scientific literature that the alloying of a second non-noble metal with platinum may result in an improvement of the electrocatalytic activity of the system. The second metal might also act as a protection for the active sites towards contaminants such as carbon monoxide or halides. These contaminants reduce the activity of the active sites of the noble metal constituting the electrocatalyst. This way it becomes possible to obtain materials showing a higher tolerance towards environmental contaminations, having a longer operating lifetime and a lower cost.